Nagios tends to define a host with check_host which requires the host to be pingable. There are various solutions that can be implemented to change that behavior, but in the case of a load balancer the definition of is it up or not is does it respond to a https:// request.

define host {

use generic-host

host_name Web-lb

alias Server hosted by ELB

address PROD-LB-...us-east1.elb.amazonaws.com

check_command check_http!-p 443 --onredirect=follow -S

contact_groups admins

}

By defining the check_command to use port 443 and allow redirects this is likely to give you results that you are looking for.